1. Field of the Invention
This invention relates to an air dryer device for drying compressed air of compressed air system, such as an air brake for a vehicle.
2. Prior Art
One conventional air dryer device as shown in U.S. Pat. No. 4,487,617 comprises a base member, a cylindrical housing mounted on the base member, an absorbent container mounted on the base member and accommodated within the housing in concentric relation thereto to form a closed space or purge chamber therebetween for storing compressed air for regenerating the absorbent material in the absorbent container. The base member has an air inlet connected to a source of compressed air, an upwardly-opening hollow portion, and an upwardly opening cavity. A plate is interposed between the base member and the housing and hence between the base member and the absorbent container. The plate covers the hollow portion to provide a valve housing in which a drain valve is accommodated. The plate also covers the cavity to provide an air passage through which the air inlet communicates with the interior of the absorbent container. With the use of the plate, the valve housing and the air passage can be provided relatively easily with a less complicated construction of the base member. A seal member is interposed between the plate and the base member. The plate is secured at its marginal portion to the base member by bolts together with the housing. It has been found that when the plate is warped or deformed upwardly toward the housing due to a pressure differential between the purge chamber and the air passage, the seal member fails to properly seal between the plate and the base member.